In modern high volume package delivery systems, a variety of material handling systems are often used. Such material handling systems often include package conveying systems that divert packages placed thereon to a variety of output destinations such as chutes, bins, and subsequent conveyor systems. Systems for diverting objects from a moving conveyor have been available for many years. Such systems are useful in discharging objects from a conveying surface at selected stations located along the path of the conveying surface.
Typical package diverting systems utilize a pusher element mounted relative to a conveying surface which when actuated ejects an adjacently placed package laterally across the conveyor surface to the desired discharge station. Many such systems guide the pusher element laterally across the conveying surface using a complex series of guide tracks or cams mounted beneath the conveying surface. Such systems are noisy and relatively difficult to repair. Additionally, the speed with which such systems eject parcels from the conveying surface is typically related to and restricted by the speed of the conveying surface.
The amount of "down time" a conveying system or sorting system is shut down for repairs and/or maintenance significantly impacts operating efficiency. Thus, reliability and ease of repair are major requirements. Reliability can be increased and down time reduced by constructing package conveying and sorting systems where mechanical assemblies may be quickly and easily removed and replaced without the use of tools. Such construction may be accomplished by use of detachable mechanical assemblies such as package diverters or by mounting mechanical assemblies on modular conveying systems such that the failed mechanical assemblies or the conveyor sections housing the failed assemblies may be quickly removed and replaced. Furthermore, because of the increased speeds required of modern package handling systems, reduction of noise levels is also a major requirement.
In U.S. Pat. No. 4,170,281 to Lapeyre, a modular conveyor belt is provided from extruded flexible links which may be either plastic or metal having ends joinable into an endless belt by an extruded substantially rigid joining member.
In U.S. Pat. No. 3,349,893 to Jordan, a segmented conveyor belt is disclosed having rigid plate sections that are joined together by flexible arch joining members. The joining members include marginal beads that are inserted into retainer grooves formed into the plates transverse to the direction of travel of the conveyor belt. Adjoining members are made of elastic, flexible materials such as rubber.
The modular diverter shoe and slat construction disclosed in U.S. Pat. No. 5,127,510 to Cotter describes a modular diverter shoe for use in a slat conveyor. A diverter shoe is mounted to each slat so that the shoe may glide across the slat. The movement of the diverter shoe is affected by a guide pin and coaxial bearing which engages a network of guide tracks located beneath the conveying surface. When a package is to be diverted, a diverting switch is actuated to switch the guide pins for the diverter shoe adjacent to the package onto a diagonal track, which causes the diverter shoe to move across the slat and eject the package.
Another apparatus for sorting objects is disclosed in U.S. Pat. No. 4,732,260 to Canziani. In that system, a conveyor belt is described in which each conveyor element has a slit. The pusher elements are slidably inserted into the slits and each pusher element is connected to a drive element that extends beneath the conveyor surface. The drive element is attached to rollers and interacts with a series of cams or guide rails located beneath the conveyor. The cams include an electro-pneumatic two-position end portion. In one position, the cam engages the drive element rollers and slides the pusher element. In a second position, the rollers do not engage the guide rails.
In some of the systems noted above, pusher elements are guided across an underlying conveying surface by interacting with a series of cams, guide rails or guide tracks located beneath the conveyor surface. It would appear that the action of the components of the moving pusher element against some of the underlying cams, guide rails and guide tracks would be a source of wear and noise. Upon failure of the underlying cams or guide components, it would appear that some of those prior art systems could undergo time consuming repair with resulting downtime for the conveying system.
Other problems associated with prior sorting systems could include the inability to eject objects from the moving conveying system at ejection speeds which are independent of the speed of the moving conveyor system. Other limitations in the prior art include limitations on the ability to eject a wide range of sizes and shapes of packages and the ability to manipulate the positioning of the object on the conveying surface prior to ejection.
As may be seen from the foregoing, prior sorting systems tend to be complex and require significant maintenance upon failure. Moreover, because such systems employ the interaction of rollers, cams and guide rails, such systems would appear to be noisy. Therefore, there has been a need in the art for a sorting system that is simple in construction, which can be easily maintained by removal and replacement of modular sortation assemblies, or conveyor sections housing sortation assemblies, without the use of tools, and which can sort and manipulate a wide range of objects at varying speeds and at relatively low noise levels.